Global Fit of Modified Quark Couplings to EW Gauge Bosons and Vector-Like Quarks in Light of the Cabibbo Angle Anomaly

Andreas Crivellin, Matthew Kirk, Teppei Kitahara +1

There are two tensions related to the Cabibbo angle of the CKM matrix. First, the determinations of $V_{us}$ from $K_{\mu 2}$, $K_{\ell 3}$, and $\tau$ decays disagree at the $3\sigma$ level.…